The present invention relates to an autotransfusion apparatus for blood or similar body fluids.
In operations such as heart surgery, vascular surgery, accident surgery or orthopedics, great and rapid losses of the patient's blood often occur. The loss of blood is usually compensated for with donated blood. However, donated blood may transmit diseases such as hepatitis. Moreover, several week old donated blood often lacks the elements of coagulation (coagulation factors and blood platelets) which are destroyed by storage. Therefore, an apparatus is needed which can recover blood entering the body cavities during an operation, and return it to the patient in order to reduce the use of donated blood and retain a large portion of the blood coagulation elements.
Complicated, expensive heart-lung machines are available today for major heart operations. The machine recovers the patient's own blood, pumps it through a pumping mechanism, and returns it to the patient through long hoses. Other kinds of machines collect the blood, isolate and wash the red blood cells and return the washed blood cells to the body. In both kinds of machines, the delicate blood cells are damaged by traveling through long tubes. In the second kind of machine, all the coagulation elements and the blood plasma are removed through the washing process. These machines are also relatively expensive and only available in a few locations.
Other devices have been developed for autotransfusion during operations. U.S. Pat. No. 4,047,526 discloses an autotransfusion system in which the blood is first drawn by vacuum into a hard container and then transferred into a bellows detachably connected at the bottom of the hard container. A vacuum can be produced by the bellows through which the vacuum in the hard container can be overcome. The bellows, filled with blood, is then detached from the hard container and then used to return the blood to the patient.
U.S. Pat. No. 4,033,345 discloses an autotransfusion apparatus with a rigid two-chamber system. An inner deformable bag is connected through a recoil valve with an upper chamber which first collects the blood. The blood can be actively transfused back into the patient through another opening within the recoil valve and filtering units by pressurizing the space between a hard second chamber and the outer surface of the bag. The conduction of the blood from the rigid collection container into the flexible bag takes place through alternate application of pressure and vacuum.
Another autotransfusion device disclosed in German Disclosure No. 32 18 561 includes a device corresponding to the second chamber of the U.S. Pat. No. 4,033,345, mentioned above. However, the blood must be suctioned out, without a recoil valve, through an opening in the under side of the chamber. A screen or a similar blood filter cannot be used with this device.
U.S. Pat. No. 4,014,329 discloses another two-chamber autotransfusion device in which the first chamber operates by the same principle as was described in U.S. Pat. No. 4,033,345 for the second chamber. However, the blood flows out, by gravity, at the under side of the chamber into the second chamber with a filter.
With these known autotranfusion devices it is possible, of course, to collect the blood occurring during the operation and to retransfuse it to the patient. However, they have a number of serious disadvantages. In the multi-chamber systems, the blood comes in contact with a large surface area, which effects a harmful activation of coagulation and traumatizing of the blood. There also takes place a further traumatizing, harmful to the delicate blood cells, in the transfer from one into the other chamber, especially when recoil valves are used between the chambers.
If the blood is suctioned from below into the vacuum chamber, the blood already accumulated in the apparatus is set in turbulent motion by subsequently suctioned blood, while air carried along, and coarse components, such as blood clots, fat cells and bone splinters, cause a considerable foam forming as well as traumatizing of the blood cells. In the absence of course filters to hold back substances carried along in the blood, there exists in the conventional fine filters provided on the transfusion instruments, a latent danger of stoppage. Moreover, blood collection chambers provided with inlet and outlet openings on the cover and bottom side, require a considerable construction height, in view of the necessary volume of blood to be suctioned, which is usually higher than the very small sterile operation zone on the patient. Therefore, in the known autotransfusion devices, there are usually problems of sterility in the sterile operation area, which can only be compensated by setting up the autotransfusion apparatus outside the sterile zone, at the cost of a longer suction distance. In this way, a higher suction pressure is necessary and there is an increased contact with foreign substances, both of which mean an additional trauma for the blood. In two chamber systems, the conduction of the large quantity of blood, after aspiration, into the second chamber, requires time, which neither the anaesthetist nor the surgeon has available. The time factor is especially harmful to the patient also, since in this case, he needs the blood back quickly.
These problems have been solved by the autotranfusion device disclosed in German Patent Application No. P 33 04 486.4. However, the problem of the air present in the autotransfusion apparatus along with the blood has remained unsolved. Before the infusion of the collected blood, the air must be removed to prevent an air embolism. The autotransfusion device can only be used so long as no air can be infused into the patient.